In the present project the influence of pH on myocardial healing-over will be investigated. The knowledge of factors involved in the healing-over process is essential for the improvement of procedures related to the rescue of myocardial fibers from the harmful effects of damage. Measurements of membrane potential and input resistance will be made at different distances from the cut-end. The experimental values of input resistance obtained near the cut-end will be compared with theoretical values for a sealed or short-circult cable. The influence of protons on myocardial healing-over will be investigated in absence of Ca ions. The search of the influence of H ions on healing-over will help to delucidate the role of pH on gap-junction permeability. The implications of these findings to cardiology are obvious.